Grain boundary structure, chemistry, and failure

The goal of this paper is to provide a review of the interrelationship between grain boundary structure, chemistry, and failure. The main thrust of the paper is that one must consider structure and chemistry in order to assess various failure mechanisms and that one must also address these issues in high angle, asymmetric grain boundaries. One of the key themes of the paper is that the boundary is best considered as a chain of molecular or structural units and that, during such processes as fracture or sliding, the ability of the boundary to sample many of these units determines whether or not a material will ultimately fail. The ease of sampling different boundary structures will depend on the chemical composition of the boundary.